Recommended 5G SIM: Frequently Asked Questions (FAQ)

To support increased momentum for 5G SIM shipments globally, Trusted Connectivity Alliance (TCA) has updated its ‘Recommended 5G SIM’ technical definition to align with new use cases introduced by 3GPP’s Release 16 Specifications for 5G Phase 2. This technical post addresses frequently asked questions to support industry understanding.

1. Is an eSIM already 5G-enabled? If not, can it be upgraded to a 5G SIM? 

An eSIM can be either 4G or 5G-enabled, but device manufacturers are mainly proposing the deployment of 5G-enabled eSIMs to unlock the full potential of 5G devices.

2. Is the set-up of the Recommended 5G SIM for network slicing similar to the set up for private networks? Or are there major differences?

In 5G networks, slicing is used to both tailor the type of service request, and also assign part of the network for the realisation of a private network.

The USIM set up is the same for both uses of slicing. Regarding the credentials, there are two types of credentials for private networks:

  • Primary authentication credentials – can be known by the public network operator if the private network relies on the MNO PLMN.
  • Secondary authentication credentials – out of scope of the public network operator.

3. What software is needed to configure a SIM?

There is no generic tool to configure the file system of the SIM, although some SIM suppliers do provide proprietary tools. For applet management, please refer to TCA’s Interoperability Loader Tool.

4. Will the Recommended 5G SIM eliminate the use of two Secure Elements (SEs) for connectivity and application security by implementing a single Tamper Resistant Element (TRE) for both 5G connectivity security and application security?

The Recommended 5G SIM will not replace the deployment of combined products (i.e. an eSIM + eSE), as it does not provide an equivalent segregation model between connectivity and application security.

5. Is there an upgrade path available from earlier release SIMs (e.g Release 8, Release 9 SIMs) to the Recommended 5G SIM?

No, as it is not only a matter of file system creation but also the underlying SIM OS capabilities (see the Recommended 5G SIM profile).

6. Is there an example of non-3GPP accesses that may be trusted by an MNO?

Yes, examples include WiFi or fixed networks.  

7. How has support for V2X evolved?

5G networks have supported V2X communication since the publication of Release 15 Phase 1, and this support has been enhanced as part of Release 16 Phase 2. Capabilities will continue to evolve as part of Release 17 and 18 (see the Recommended 5G SIM profile).

8. In a SIM with multiple home operator public keys, how is the selection performed?

Multiple home operator public keys are allowed within the SIM profile. The selection of the key is not open, but specified by standards. The entity performing the SUPI computation (either the SIM or device) select the key associated with a supported encryption scheme. If the SIM or device does not support the scheme, then it switches to the next key.  

9. Will devices support Steering of Roaming?

Enhanced Steering of Roaming (SoR) depends on the technical roadmaps and strategies of individual device manufacturers, but has been supported by the 3GPP standards since the introduction of toolkit enhancements in Release 15.

10. What features are not available in a non-standalone 5G network?

All major innovations compared to 3G and 4G technologies are unlocked with 5G Standalone networks (SA), where a 5G Core is integrated with a 5G radio.

A non-Standalone (NSA) 5G network is a hybrid version of 5G, where the 5G radio network is connected to an Evolved Packet Core (EPC) network. Within this deployment scenario, there are limited enhancements to the capabilities and functionality of the SIM.

11. Is there a concrete example of how the Recommended 5G SIM will address 5G ecosystem fragmentation?

One clear example of the Recommended 5G SIM addressing 5G ecosystem fragmentation is the issue of subscriber privacy. Performing SUPI encryption within the device creates a complex qualification process due to the diversity of brands, models and operating systems. In contrast, delegating SUPI encryption to the Recommended 5G SIM supports a simple and streamlined qualification process. To find out more, download TCA’s white paper.